An Army sergeant who shot herself in an office Monday at the Fort Lee installation near Richmond, Va., has died, the Army said.

The soldier, who has not been identified, died after barricading herself in an office inside a major command headquarters. Fort Lee officials said the soldier was pronounced dead Monday after being taken to Virginia Commonwealth University Medical Center in Richmond. No other injuries were reported in the morning shooting.

Maj. Gen. Stephen Lyons said the incident happened on the third floor of the four-story building that houses the Army's Combined Arms Support Command (CASCOM). Lyons said about 1,100 people were inside the building at the time. No other injuries were reported.

Officials said the soldier went on a rampage in the office, throwing objects. Fort Lee temporarily went on lockdown during the standoff. Officials said the soldier was a sergeant first class who had been in the Army for 14 years and at Fort Lee for three. Her gun wasn't a service weapon, the Army said.

On its Facebook page, Fort Lee said first responders reacting to a report of a female soldier with a gun inside CASCOM headquarters at about 9 a.m. found that the soldier had apparently turned the weapon on herself and fired one shot. The Army said special agents from the U.S. Army Criminal Investigation Command were investigating the incident.

"Fort Lee officials take this incident very seriously and are fully cooperating with the investigation," the statement said

The post was put on lockdown briefly. The post's Twitter and Facebook accounts instructed all personnel to "enact active shooter protocols immediately." The Army sent an "all clear" message about 20 minutes later.

The lockdown came just four days after the Army announced the installation of a new mass warning and emergency notification system, to be activated within weeks. Called "Fort Lee Alert," it is intended to "greatly increase the installation's ability to disseminate important and, possibly, life-saving information," James Livingston, an Army operations specialist, told the Fort Lee Traveller, the installation's command-authorized newspaper.

The alert system is being fielded at Fort Lee as part of the Army's Emergency Management Modernization Program, the paper said.

CASCOM is a training and education center located on the post about 20 miles south of Richmond.